Abstract A simple calorimetric technique was used to estimate the temperature of balls during mechanical alloying (MA) in an AGO-2 planetary ball mill. Temperatures up to 600 °C were realized for balls in the case that compact layers of milled powder are formed on the surface of the balls and the wall of the vial. Though free powders in the vial would decrease the temperature of the balls, it was found that a difference in temperature between the balls and the vial still exists. This should be taken into account in the analysis of temperature effects during MA. An influence of the temperature of the balls on the MA process of Mg 67Ni 33 and Ni 50Al 50 powder blends was demonstrated.